1. Field of the Invention
The present invention relates to a method of determining optimum recording power in optical disc apparatus for recording information by irradiating optical discs with a laser beam.
2. Related Art
Optical discs have been extensively developed as a means for recording a large volume of data, and for one of them, there is a write-once type optical disc which utilizes the state change of organic pigment and can record information once only in one same place. In the optical disc that uses organic-based pigment for recording film, the vapor pressure in the vicinity of the surface of the recording portion is raised by irradiation of an optimum light beam and presses to expand the melted portion to the periphery to form a pit.
In recording information to such a kind of optical disc, it is important to optimize the irradiation power of light beam, and accordingly a method of carrying out test recording in the predetermined area of the optical disc has been extensively adopted. In such event, since the area once recorded cannot be reused in the write-once type optical disc, it is necessary to search for the unused area for carrying out the test recording. For example, the unused area can be found by detecting the reflecting light quantity by scanning the test recording area with light beam, using the difference of reflectance between the used area and the unused area.
However, because by the conventional technique, in the area where even though recording was carried out, the recording was not satisfactory due to, for example, stains of light pickup, etc., there was a problem in which changes of reflecting light quantity were small. Thus the used area was mistakenly judged to be an unused area during searching the test recording area and the test recording was carried out thereto.